The present invention relates to an improved pressure balance device which is made up of a pair of symmetric half cylindrical units and a water inlet cap. The two semi-cylindrical units are put in abutment against each other and the water inlet cap can be pushed from the top of the semi-cylindrical units all the way down so as to make the assembly easier and faster as a result of reduction of components and steps in assembly.
Referring to FIG. 1, a typical conventional pressure balance device is comprised of a pair of semi-cylindrical cases 10, a water inlet cap 20 and a restraint ring 30. Each case 10 has a vertically cut flat face with a receiving chamber 11 defined thereon so as to permit a balance shaft 12 to be housed therein On the top surface of each case 10 is disposed a limiting protrusion 15 and at the bottom is disposed a retaining projection 16. On the sides of the vertically cut plane of each semi-cylindrical cases 10 are also disposed a pair of retaining rods 13 and a pair of retaining holes 14 respectively. As shown in FIG. 1A. the water inlet cap 20 of a proper thickness is circular in structure with a cross-shaped groove 21 disposed under the bottom thereof.
In assembly, as shown in FIG. 2, the two semi-cylindrical cases 10 are placed with their vertical flat faces in abutment against each other, permitting the retaining rods 13 of each semi-cylindrical case 10 to be engaged with the retaining holes 14 of the other semi-cylindrical case 10 respectively. The limiting protrusions 15 on the two semi-cylindrical cases 10 are in abutment with each other to form a cross-shaped block in fitting conformance to the cross-shaped groove 21 of the water inlet cap 20 so that the cap 20 and be engaged firmly with the two semi-cylindrical cases 10 in assembly. At last the restraint ring 30 is put into engagement with the retaining projection 16 of the assembled semi-cylindrical cases 10 to complete the assembly.
Such a prior art pressure balance structure has the following disadvantages:
1. Its assembly components are relatively numerous, and it requires many molds to produce, resulting in the costs of production relatively high PA1 2. It takes more steps to assemble the semi-cylindrical cases 10 and the water inlet cap 20 and the restraint ring 30 together, making the assembly tedious and time consuming.